Conventionally, to ensure water evacuation performance on a wet road surface, a method in which multiple circumferential grooves are formed in a tread has been widely used for a pneumatic tire (hereinafter referred to as tire) mounted on a passenger car or the like.
In addition, a tire is known in which, for active evacuation of rainwater entering such circumferential grooves, multiple protrusions inclined relative to the tire circumferential direction are provided on groove bottoms of the circumferential grooves (for example, Patent Document 1). It is said that such a tire facilitates the creation of helical flews of rainwater entering the circumferential grooves, so that the water evacuation performance is improved.